GLP-1 receptor agonist use may reduce quality of colonoscopy bowel preparation

New research suggests that patients taking glucagon-like peptide-1 (GLP-1) receptor agonists for diabetes or obesity management have a significantly lower quality of colonoscopy bowel preparation and a greater need for repeat colonoscopy. Researchers at the Mayo Clinic in Rochester, Minnesota investigated this issue, as GLP-1 agonists (e.g., dulaglutide, liraglutide semaglutide) are known to reduce gastric emptying and slow gastrointestinal motility.1 The retrospective cohort study included patients who underwent outpatient screening or surveillance colonoscopy at a large academic medical centre during a one-year period. The study included patients taking any GLP-1 agonist for diabetes or obesity management at the time of colonoscopy (cases group). Patients who were prescribed GLP-1 agonists at one point, but not within three months of colonoscopy, acted as the control group.1 Patients on any promotility or antimotility agents (opioids, antidiarrheals, anticholinergics, prokinetic agents) within the three-month period prior to the colonoscopy were excluded from the study. Also excluded were patients who did not have a Boston Bowel Preparation Scale (BBPS) value recorded on their procedure report (the BBPS is used to assess the quality of bowel preparation).1 Results showed the following: A total of 446 patients were included in the study: 265 (59%) cases and 181 controls (41%). No statistically significant differences between groups were noted at baseline except for the diagnosis of diabetes, with a higher proportion of patients with diabetes in the cases group (86% in the cases group vs 74% of controls, p=0.001). Of the case patients, 48.8% received subcutaneous semaglutide, 3.1% oral semaglutide, 34.6% dulaglutide, 11% liraglutide, and very small percentages received tirzepatide or exenatide. Mean BBPS was significantly higher in controls (7.0 ± 1.9 vs. 7.5 ± 2.4, p=0.046), after controlling for diabetes. (Diabetes is a known risk factor for suboptimal bowel preparation in patients undergoing colonoscopy.) The percentage of patients with a total BBPS score of < 5 was significantly higher in the cases group (15.5% vs. 6.6%, p=0.01). The proportion of patients who required a repeat colonoscopy due to poor bowel preparation was significantly higher in the cases group (18.9% vs. 11.1%, p=0.041). This corresponded to a number needed to harm of 14.1 The authors conclude that use of GLP-1 receptor agonists is associated with a statistically significantly lower quality of bowel preparation and an increased need for a repeat colonoscopy. They note that a Canadian review article recommends holding GLP-1 agonists prior to colonoscopy in patients with diabetes, in part due to the possible impact on bowel preparation, pre-procedure nausea leading to the increased likelihood of rescheduled colonoscopy, and risk of acute kidney injury secondary to volume depletion.3 The Mayo Clinic researchers believe their study is a valuable addition in support of this recommendation; however, they indicate that further prospective data are needed to determine whether such a strategy would have a clinically meaningful impact. They contend that further research is also needed to evaluate whether GLP-1 agonists have a dose-dependent effect on bowel preparation, and whether the effect depends on duration of use or varies with specific drugs within the GLP-1 agonist class. The authors stress the importance of determining the effect of medications that may delay gastric emptying on the quality of bowel preparation, so that appropriate measures and counselling can be undertaken before undergoing outpatient colonoscopies. Repeated colonoscopies increase direct procedural costs and also lead to additional indirect costs, including patient time off work, potential complications, and possible impact on endoscopy suite availability.1 In commenting on the study results, investigator Dr. Eric. J. Vargas, of the Mayo Clinic in Rochester, Minn. stated that, "Clinicians should consider patients on GLP-1 receptor agonists to be a population at risk for poor quality of bowel preparation. Specifically, for every 14 patients treated with GLP-1 receptor agonists, one patient would require a repeat colonoscopy due to suboptimal preparation."2 Dr. Vargas also stated that "We will continue gathering more information on colonoscopy preparations and GLP-1 receptor agonist medication use, and whether the newer type 2 diabetes medications have a similar effect. The newer and upcoming medications are double and/or triple agonists, and it remains to be determined if these have a similar effect on gastric transit times."2 References 1. Yao R, Gala K, Ghusn W, et al. Effect of glucagon-like peptide-1 receptor agonists on bowel preparation for colonoscopy. Am J Gastroenterol 2023; published online October 19, 2023.(accessed November 27, 2023). 2. Larkin M. GLP-1 RAs tied to suboptimal bowel prep, repeat colonoscopy. Medscape Pharmacists, November 20, 2023. (accessed November 27, 2023). 3. Chirila A, Nguyen ME, Tinmouth J, et al. Preparing for colonoscopy in people with diabetes: a review with suggestions for clinical practice. J Can Assoc Gastroenterol 2022;6(1):26-36. (accessed November 27, 2023).

GLP-1 receptor agonist use may reduce quality of colonoscopy bowel preparation

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